Actually some rental places with exit gates are starting to move away from this and going to QR codes loaded onto a smartphone.

In fact on a recent rental I tried to just hand the attendant my DL when exiting, but he instead strongly encouraged me to just use my phone.

“We’re trying to teach all our customers how to use their phones to exit the gates”, as he explained. Kind of the opposite scenario to the one that started this thread now that I think about it.